1. Field of the Invention
This invention relates to therapeutic agents and peptides, radiotherapeutic agents and peptides, radiodiagnostic agents and peptides, and methods for producing such labeled radiodiagnostic and radiotherapeutic agents. Specifically, the invention relates to cyclic peptide derivatives and analogues of somatostatin, and embodiments of such peptides labeled with gamma-radiation emitting isotopes such as technetium-99m (Tc-99m), as well as methods and kits for making, radiolabeling and using such peptides to image sites in a mammalian body. The invention also relates to peptide derivatives and analogues of somatostatin labeled with cytotoxic radioisotopes such as rhenium-186 (.sup.186 Re) and rhenium-188 (.sup.188 Re), and methods and kits for making, radiolabeling and using such peptides therapeutically in a mammalian body.
2. Description of the Prior Art
Somatostatin is a tetradecapeptide that is endogenously produced by the hypothalamus and pancreas in humans and other mammals. The peptide has the formula: